Even men who don’t conjure Channing Tatum when stripped to their skivvies still feel passionate about their underpinnings. One man’s quest to find perfection.

A man’s undershirt, if he wears one at all, is usually an afterthought, something that is hidden out of sight by a dress shirt. My grandfather wore one under his Brooks Brothers oxfords: the white, ribbed, sleeveless kind known as — excuse the expression — a “wife beater,” like the one Marlon Brando wore in “A Streetcar Named Desire.” My father still wears crew-neck Hanes undershirts that he buys by the three-pack and that peek out of his dress shirts when he wears them without a tie on the weekend.

For many years, I wore no undershirt, perhaps to rebel against my father, who used to also insist that I wear a hat when it was cold outside. After years of freezing in the winters and sweating through shirts in the humidity of Manhattan summers, I broke down and bought some. But I couldn’t stand seeing the white peek out every time I loosened my collar. I experimented with V-necks, but they too can become visible unless the shirt is fully buttoned up. They all add bulk. If you’re wearing a slim-fit or custom dress shirt, an undershirt can make you think you should go up a size. And they all ride up your torso throughout the day, adding even more heft to your waistline, creating a bunched-up affair that makes doing situps at the gym worthless. You can shove the bottom of the undershirt down the elastic band of your underwear, hoping it will stay there, but that doesn’t help much and is quite uncomfortable. I tried them all: Calvin Klein, Ralph Lauren, 2(x)ist, Jockey, Uniqlo, Hanes, you name it.

MPTV ImagesGroucho Marx showing some leg and his socks in “Duck Soup” in 1933.

Until I found the perfect undershirt. It is made by a company called Tommy John (unrelated to the baseball player). It changed my life. Before I go any further, let me say the cost of these shirts is indefensible: $40 apiece! For an undershirt! (I secretly hope someone from Fruit of the Loom will read this article and figure out a way to knock them off for a third of the price.)

If you’re wondering what could possibly be so special about this undershirt, let me try to explain: First, it is remarkably soft, a little silky. Like a cashmere sweater. It is thin. Really thin. It’s not sheer, but it could be. When you’re wearing it, you almost forget it’s on.

It’s stretchy, but not like compression shorts or a girdle. It’s made out of a combination of cotton or micromodal and spandex, depending on which model you buy.

And the V-neck is wide enough that it’s impossible to see from any angle even if you undo the top two buttons of your shirt. Having said all that, you’d look absolutely silly wearing one of these undershirts without a shirt on top of it — unless you’re Channing Tatum. My wife says it looks like a “party dress” given how low the shirt falls on your torso. But that’s part of its brilliance — and that’s why it never becomes untucked.

Ever since I bought my first Tommy John undershirt over a year ago, I have been touting it to just about anyone who will listen to me. Men, I’ve discovered, care more about their undergarments than you might think and seem more brand-loyal than their label-promiscuous female counterparts. They spend $2.6 billion a year on underpants alone, according to NPD Group, up 17 percent over the past year. The men’s underwear business has come a long way since Mark Wahlberg stripped down to his boxers on a giant Times Square billboard in 1992 to hawk Calvin Klein briefs. Since then, dozens of new high-end and low-end men’s undergarment brands have emerged. I know a senior Hollywood executive who will wear only $58 boxer briefs made by Hanro in Switzerland. He too extols their virtues to anyone who will listen. Another entertainment executive wears only $110 cashmere Ralph Lauren Purple Label socks. On the other side of the price spectrum, I have a friend who claims to exclusively wear boxer briefs from H&M’s David Beckham line. The cost: $12.95 for a three-pack. Ask around and you will find out about the passion men are secretly tucking away under their clothes.

Two months ago, I ran into Sara Blakely, the founder of Spanx, which has upended the women’s undergarment market by virtually creating an entirely new category called shapewear. Now Blakely has set her sights on the men’s market. Given my interest in undershirts, naturally I have been testing hers. At $58, they’re pricey, but if you haven’t been to the gym in a while and have a little extra to hide, this shirt will do the trick. And, oddly enough, it seems to provide back support. But after an hour or two in the shirt, you could get a little claustrophobic. She’s coming out with shirts soon that are less tight, which seem more my type.

In the meantime, I told her about Tommy John. She bought one for her husband to try.